This invention relates to medical diagnostic apparatus. More specifically, this invention relates to a fiber optic illuminating assembly for lighting the bore of a magnet forming part of a magnetic resonance (MR) scanner, with respect to which the preferred embodiment of the invention is disclosed.
An MR scanner typically comprises a magnet, often of superconductive design, of generally solenoidal geometry having a longitudinal bore for receiving the object to be examined. In medical diagnostic applications, the object is a patient so that it is desirable to enhance patient comfort and to allow visual contact between the patient and attending personnel. Such considerations are particularly important with very ill patients. To this end, it is advantageous to illuminate the bore, which in the case of a whole-body MR scanner can be approximately 8 feet long.
Illumination of the bore, however, cannot be accomplished simply using conventional techniques due to the highly magnetic environment in the vicinity of the magnet. For example, fields of 1.5 Tesla, or more, are typically employed in MR scanners using superconductive magnets. Additionally, because of the relative weakness of the MR signal sought to be detected in the course of scanning a patient and the concomitant need to maximize the signal-to-noise ratio, it is essential that interference from all sources be minimized. In fact, MR scanners are frequently housed in RF opaque screen rooms providing about 90 db of bidirectional radio frequency (RF) attenuation. Further, because of the magnetic environment and the proximity to the RF coils used to excite and detect MR signals, no electrically conductive or magnetic materials can be used within the bore of the scanner. This requirement dictates the need for a remote light source to illuminate the bore. Such a light source must, of course, be consistently producible at an economical cost. Another factor which must be considered is the life expectancy of the components used due to the aforedescribed magnetic environment.
It is, therefore, a principal object of the invention to provide an illuminating device which meets the stringent reliability and operability requirements for use with an MR scanner.
It is another object of the invention to provide an illuminating device which is consistently producible at an economical cost.
It is still another object of the invention to provide an illuminating device which uniformly illuminates the bore of an MR scanner.